PORTSMOUTH — “Silent Strength,” the hardcover edition of D. Allan Kerr’s profiles celebrating some of the remarkable men lost aboard the nuclear submarine USS Thresher, is being published this April by Peter E. Randall Publisher in Portsmouth.

Those interested in purchasing the book (with the working subtitle Remembering the Men of Genius and Adventure Lost in the World’s Worst Submarine Disaster) – can pre-order copies thru the Thresher Memorial Project Group at a discount. The book will sell for $29.99 upon publication, but those who pre-order can purchase a copy for $24.99.

What’s more, folks sending in $75 can be listed as sponsors within the pages of the book. The $75 total includes the purchase. However, in order to have your name printed in Silent Strength, your contribution must be submitted by February 15.

$50 of the $75 payment made through the Thresher Memorial Project Group is tax-deductible — minus the value of the book — as the group is sponsored by the Kittery Maine Improvement Foundation, a 501(c) (3) non-profit corporation.

U.S. Sen. Susan Collins of Maine has written a foreword for the collection. Most of the chapters appeared as newspaper articles in the Portsmouth Herald in a year-long series leading up to the tragedy’s 50th anniversary on April 10, 2013, but new ones have been added as well. Several of those profiled were Seacoast natives.

The Kittery, Maine, memorial includes a 129-foot flagpole commemorating the 129 men who died aboard the Thresher that April morning of 1963. An adjacent park currently under construction near Town Hall features a bronze plaque listing the names of those who perished, and a black granite carving of the Thresher recently donated by local sculptor Thomas Berger.

The park also honors veterans from all military branches. A water stone located at the site is being named for Kittery’s own Gen. William Whipple, the only Maine native to sign the Declaration of Independence.

The Thresher (SSN 593), designed and built at Portsmouth Naval Shipyard in Kittery, was the most advanced naval vessel of its era. She was created to hunt and destroy Soviet submarines at the very height of the Cold War. The Thresher sank during deep-diving tests off the New England coast following a nine-month overhaul at the shipyard.

Vis Tacita, Latin for “Silent Strength,” was the submarine’s motto.

Copies of Silent Strength delivered through the mail will require an additional postage fee of $5.95. Pre-order buyers in the Seacoast area can pick up their copies at a special event to be scheduled during Thresher anniversary events in April.